FAQ: “Does HunterLab have any documentation to show that the ColorQuest XE is compliant with ASTM 1209. One of our customers is having a problem regarding the method. Their client is using the manual visual method for performing the ASTM 1209 color test method whereas they use the ColorQuest XE. Can you explain the difference?”
FAQ: “… I just need to find a way to better condition the samples for consistency. I can get some pretty consistent results on my own, but once it’s in a general QC lab, it’s going to need some standardization.”
These APHA/Pt-Co/Hazen liquid color standards were originally developed as references for visual APHA/Pt-Co/Hazen Color comparison to samples. Their role with instrumental APHA/Pt-Co/Hazen Color measurement is primarily as a performance qualification check of the instrument prior to measuring liquid product samples, or to validate the instrumental-to-visual correlation. HunterLab instruments have their own internal diagnostic standards to verify […]
There are no physical liquid standards specifically designed to verify the Yellowness Index of liquid samples over time. Yellowness Index is defined as a mathematical function such that a perfect clear of 100% transmission, typically represented by the transmission cell filled with DI water, will have a YI value of 0. However, a good workaround solution […]
HunterLab’s round cell (A13-1011-613) is a practical small volume cell for transmittance color and haze measurements.
EasyMatch QC-ER is a 21 CFR Part 11 compliant version of HunterLab’s EasyMatch QC software for electronic records. Here is how to successfully upgrade to a newer version on the same computer.
The original references were written by Allen Hazen, a chemist who first defined APHA/Pt-Co/Hazen color scale for the evaluation of water quality on behalf of the American Public Health Association: Hazen, A. A new color standard for natural waters, American Chemist Journal (14:300), 1892. Hazen, A. The measurement of the colors of natural waters, American […]
FAQ: “We are in touch with a pharmaceutical company which is looking for a spectrophotometer to measure the color and appearance of cationic surfactants. Can you provide any information on this topic?” Surfactants reduce the surface tension of a liquid as in the use of a dish detergent; the interfacial tensions between two liquids such as in the case of […]
There are several parts to the 21 CFR Part 11 documents with a good overview of 21 CFR Part 11 at the US FDA website. Part C is the key section concerned with electronic records retention.
“APHA” stands for American Public Health Association Color Scale, the organization responsible for the original definition and implementation of this visual color scale as a standard method for rating water quality.